What reagent is typically used for substitution with cyanide ions (CN-)?

The typical reagent used for substitution with cyanide ions (CN-) is potassium cyanide in ethanol. In nucleophilic substitution reactions, cyanide ions can act as strong nucleophiles due to the negative charge on the carbon atom, which is highly electronegative. The presence of potassium cyanide in ethanol not only provides the cyanide ions necessary for the reaction but also serves as a suitable solvent that can stabilize the charged species involved in the process.

In nucleophilic substitution, the cyanide ion attacks an electrophile, often an alkyl halide, leading to the substitution of the halide with the cyanide group. This results in the formation of nitriles, which are important functional groups in organic chemistry.

The other options involve substances that do not provide the necessary cyanide ions or the required conditions for carrying out a nucleophilic substitution with cyanide. For example, potassium iodide does not have a relation to the cyanide ion mechanism, while sodium chloride is predominantly used in reactions involving sodium ions and does not provide the necessary nucleophile. Ammonium sulfate is primarily used as a salt and does not contribute to nucleophilic substitution reactions.